Pool tile thin-set suggestions?

We are getting a new IGP Marcited this week and want to use a couple pieces of the border tiles as inlays on the steps and swim benches. I am worried the Marcite folks will not place them to my preference so I am thinking I might glue them down ahead of time. (they are shaped like wave pieces that I want to place 2 together to form a square so placement is more critical than normal). A local tile place said to just make a loop of tape to bond them to the shell and let Marcite hold them by the edges but I worry about them coming lose. Home Depot tile guy recommended a concrete acrylic adhesive. Didn't love that either. I am not sure what the pool Co. used to do the border tiles but figure same thin-set would be best. I should preface this with I have zero tiling experince. I would rather have nothing than screw this up so worried about the deal now. Advice from those in the know? BTW: as a new pool owner I love this site...I have learned more here in a week than I ever thought I could.

The area that is going to be under the tile put a thin coating of hydraulic cement (smooth and level) but with a very slight texture (extra grip for thinset), this will water proof the concrete pool surface. Then you can use thinset to set your tiles. Use a modified thinset at Home Depot or Lowes. Use grey thinset if your plaster is going to be dark and a white if your plaster is going to be white. Make sure to leave room between the tiles for the plaster (you do not want to fill between the tiles with thinset, you want the plaster to fill between the tiles). Almost forgot hydraulic cement is called Water Stop at Home Depot or Lowes
Hope this helps.